They show up on eBay fairly regularly. There are two types, the '52-'53 type with a trim strip fore and aft of the emblem, and the later one you need, it fits '54-56. The Sportster tank is similar but has cutouts in the base for the taller engine and is set-up for different emblems. They tend to be expensive if in decent shape! Good luck!Robbie

While on the subject of 56 KHK tanks, I have one that someone has removed the badge mounting bracketry from and I am wondering how to deal with this. I have heard that the MoCo has reproduced the '56 swoosh emblem and that it comes with foam tape for mounting (which I really don't want to do), but lacking the correct mounting bracket, I'm not sure how to proceed. So, if anyone could post a picture of the correct mounting bracket and/or offer any advice on a path forward it would be welcomed. Thank you.

I have heard that the MoCo has reproduced the '56 swoosh emblem and that it comes with foam tape for mounting

Not quite, the kit is 4 parts, 2 emblems and 2 brackets with foam tape. So if you remove the foam tape, you can tin them and solder them in position. The OEM mounting was with spot welds for speediness, nothing to prevent you from soldering it...